The authors found that the growth rates and height of the children increased with vitamin D supplementation, and that there was a significant correlation between serum concentrations of IGF-1 and the percentage increment in 25(OH)D concentrations, with IGF-1 concentrations increasing significantly after treatment with vitamin D. Both the length and the growth rate correlated with the IGF-1 concentration, leading the authors to conclude that the growth spurt observed in children with rickets after vitamin D supplementation is mediated via through an increase in IGF-1 (Soliman et al., 2008). The gene discussed is IGF1; the disease is rickets.